title: Flexibility of the programme of spore coat formation in Bacillus subtilis: bypass of CotE requirement by over-production of CotH.
abstract: Bacterial spores are surrounded by the coat, a multilayered shell that contributes in protecting the genome during stress conditions. In Bacillus subtilis, the model organism for spore formers, the coat is composed by about seventy different proteins, organized into four layers by the action of several regulatory proteins. A major component of this regulatory network, CotE, is needed to assemble the outer coat and develop spores fully resistant to lysozyme and able to germinate efficiently. Another regulator, CotH, is controlled by CotE and is present in low amounts both during sporulation and in mature spores. In spite of this CotH controls the assembly of at least nine outer coat proteins and cooperates with CotE in producing fully resistant and efficiently germinating spores. In order to improve our understanding of CotH role in spore formation, we over-produced CotH by placing its coding region under the control of a promoter stronger than its own promoter but with a similar timing of activity during sporulation. Over-production of CotH in an otherwise wild type strain did not cause any major effect, whereas in a cotE null background a partial recovery of the phenotypes associated to the cotE null mutation was observed. Western blot, fluorescence microscopy and Surface-Enhanced Raman Scattering spectroscopy data indicate that, in the absence of CotE, over-production of CotH allowed the formation of spores overall resembling wild type spores and carrying in their coat some CotE-/CotH-dependant proteins. Our results suggest that the B. subtilis spore differentiation programme is flexible, and that an increase in the amount of a regulatory protein can replace a missing partner and partially substitute its function in the assembly of the spore coat.
authors.affiliation: Department of Biology, Federico II University, Naples, Italy.
authors.forename: Rachele
authors.initials: R
authors.lastname: Isticato
authors.forename: Teja
authors.initials: T
authors.lastname: Sirec
authors.forename: Rosa
authors.initials: R
authors.lastname: Giglio
authors.forename: Loredana
authors.initials: L
authors.lastname: Baccigalupi
authors.forename: Giulia
authors.initials: G
authors.lastname: Rusciano
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pesce
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Zito
authors.forename: Antonio
authors.initials: A
authors.lastname: Sasso
authors.forename: Maurilio
authors.initials: M
authors.lastname: De Felice
authors.forename: Ezio
authors.initials: E
authors.lastname: Ricca
mesh_terms: D001412:Bacillus subtilis / Q000166:cytology / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D009154:Mutation; D010641:Phenotype; D011401:Promoter Regions, Genetic / Q000235:genetics; D013059:Spectrum Analysis, Raman; D013171:Spores, Bacterial / Q000166:cytology / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C077494:CotE protein, Bacillus subtilis; C101016:CotH protein, Bacillus subtilis